Section 420.07 - Effluent limitations guidelines and standards for pH(a) The pH level in process wastewaters subject to a subpart within this part shall be within the range of 6.0 to 9.0.(b) The pH level shall be monitored at the point of discharge to the receiving water or at the point at which the wastewater leaves the wastewater treatment facility operated to treat effluent subject to that subpart. 67 FR 64261 , Oct. 17, 2002